Scissortail Rasbora Fish Species Profile

Characteristics, Origin, and Helpful Information for Hobbyists

Scissortail Rasbora

I, Lerdsuwa / Wikimedia Commons / CC BY-SA 3.0

The scissortail rasbora is a sleek, streamlined fish named for its deeply forked tail, which resembles an open pair of scissors. The distinct bar pattern on the tail fin accentuates the scissor-like shape. This active fish cuts through the water, and when swimming and even while at rest, this fish will open and close its tail in a scissor-like fashion, giving rise to the common name for which it’s best known. The scissortail rasbora has a silver iridescence that shimmers and sparkles as it reflects ambient light.

Species Overview

Common Name(s): Black scissortail, scissorfish, scissortail, scissortail rasbora, scissortail shark, spot-tail rasbora, three-lined rasbora

Scientific Name: Rasbora trilineata

Adult Size: 3.5 inches (8 cm)

Life Expectancy: 5 years

Characteristics

Family Cyprinidae
Origin Borneo, Cambodia, Laos, Malaysia, Sumatra, Thailand
Social Peaceful, schooling fish
Tank Level Top to mid-dwelling
Minimum Tank Size 20 gallon
Diet Omnivore
Breeding Egg scatterer
Care Easy
pH 6.6 to 7.0
Hardness 2 to 12 dGH
Temperature 73 to 78 F/23 to 25 C

Origin and Distribution

Rasbora trilineata, commonly know as the scissortail rasbora, originates from the southern Mekong River basin in Cambodia, Laos, and Thailand, as well as from the Malaysian peninsula and the islands of Borneo and Sumatra. Most often found in slow-flowing rivers and swamps in forested areas, scissortails have also been found in rapidly flowing hillside streams as well as lakes and reservoirs. Most specimens sold in the aquarium trade are captive bred rather than wild-caught.

Colors and Markings

Also known as the three-lined rasbora, this fish is a hardy and popular member of the Rasbora group. Slender, with an almost transparent body, a horizontal black line runs from behind the gills to the tail. The tail is forked, and bears bands of yellow and black, ending with a band of white at the tip, giving its common name of the three-lined rasbora. 

Tankmates

Preferring to live in schools of a half dozen or more, the scissortail grouping is quite active. They are peaceful, gregarious fish that do well in community aquariums. They should be kept with at least a half-dozen of its own kind, to bring out their colors and make them feel at home. Other species of rasboras make excellent companions for scissortails.

Virtually all tetra species are good tankmates, as well as danios, gouramis, and even some larger fish such as the angelfish and discus. Bottom-dwelling fish such as corys and other catfish species also make good tankmates. Even livebearing fish such as guppies, mollies, and swordtails can be kept with scissortails. Just keep in mind that some of those species do better in more alkaline water versus the slightly more acidic water that the scissortails prefer.

Scissortail Rasbora Habitat and Care

Scissortail rasboras require an open swimming area and do best in longer tanks. Although not fussy about décor, the most natural setting would be one that includes plants such as Java moss, driftwood, and rocks of various sizes to mimic a riverbed habitat. Subdued lighting will recreate the typical forested habitat, however, scissortails will adapt to a wide range of habitats.

When preparing a tank, filtration is important, as scissortails require good quality water. They are naturally accustomed to moving water and would enjoy a current such as that provided by a powerhead. The use of peat or blackwater additives can help replicate the optimum water parameters. A darker substrate is preferred, and the tank should be tightly covered, as scissortails are prone to jumping.

When finally bringing this species home, it is wise to match water parameters from the tank they came from, as closely as possible, as they do not adapt well to sudden changes in water conditions. Take care to acclimate them for a few hours to ensure they are not shocked.

Scissortail Rasbora Diet and Feeding

Scissortails readily accept all foods but prefer to eat live foods whenever possible. In nature, their diet consists primarily of insects. However, they will accept frozen foods and freeze-dried foods as well as flake foods. Brine shrimp, daphnia, and any type of worm are excellent supplemental foods, particularly when conditioning before breeding.

Gender Differences

Sexual differences in scissortails are not readily discernible. Males are typically smaller and more slender than females. When ready to spawn, males are more intensely colored. Females are generally larger and rounder in the belly, particularly when viewed from above.

Breeding the Scissortail Rasbora 

Scissortails are egg-scatterers that are relatively easy to breed. A separate breeding tank is recommended; it should be fitted with either a mesh for the eggs to fall through or spawning mats. Fill the tank about half full of water that is slightly acidic (6.0 to 6.5) and at a temperature of 77 to 82 degrees Fahrenheit (25 to 28 Celsius). Lighting should be minimal, and it is best to use a sponge type filter.

Condition adults with live foods, such as bloodworms, daphnia, and brine shrimp to prepare for spawning. When the female is full of eggs, place a few pairs in the breeding tank. To induce spawning, add small amounts of colder, softer water several times throughout the course of the day. Continue feeding live, or frozen live foods, until spawning takes place.

The breeding pair will make several deposits of adhesive eggs over the spawning medium. Once eggs have been laid, the adults should be removed promptly, as they will readily eat their own eggs. The eggs are sensitive to light and fungus, so lighting should be minimal, and the tank should be kept very clean. Frequent water changes are recommended as well as the use of antifungal treatment in the water as a preventative measure.

After approximately 24 hours, the eggs will hatch; fry initially feed off the egg sac. After another two days, the fry become free-swimming and must be fed freshly hatched brine shrimp and other small fry foods.

More Pet Fish Species and Further Research

If scissortail rasboras appeal to you, and you are interested in some compatible fish for your aquarium, read up on:

Check out additional fish breed profiles for more information on other freshwater fish.